1. Field of the Invention
This invention relates to a revolver assembly of a microscope designed to change the magnification of the microscope by a rotary switching operation of selecting an objective lens out of a plurality of lenses.
2. Description of the Related Art
FIG. 14 of the accompanying drawings schematically illustrates a known microscope designed to change the magnification of the microscope by a rotary switching operation of selecting an objective lens out of a plurality of lenses. Particularly when a large number of specimens are observed through a microscope of this type, for instance, for clinic screening, an operator places a single specimen on stage 1 at a time for observation on a one-by-one basis. Then, the operator has to operate focusing handle 2, stage handle 3, lighting control knob 4 and revolver 5 frequently to observe the specimen. The stage handle 3 can be moved horizontally to move the specimen.
The revolver 5 is fitted to the known microscope at a considerably elevated position relative to the focusing handle 2, the stage handle 3 and the lighting control knob 4 if viewed from the stage 1 (upper surface). In other words, as seen from FIG. 14, the revolver 5 is rather separated from the remaining components of the microscope to be operated for observing the specimen and, at the same time, disposed opposite to said remaining components relative to the stage 1.
Thus, the operator has to intentionally extend one of his or her arms in order to operate the revolver 5. This action of extending the arm gives rise to considerable fatigue on the part of the operator if repeated for screening a large number of specimens. Additionally, the arrangement of the revolver 5 at a position considerably elevated from the remaining components that are disposed substantially on a same level and hence can be operated rather easily for observing specimens provides a problem of poor screening efficiency particularly when a large number of specimens are inspected.
Still additionally, the revolver 5 is placed right above objective lens 6 and right below body tube 8 having eyepiece 7. Thus, the operator is required to do a cumbersome action of extending one of his or her arms upward and then making it creep under the arm section 91 of the frame 9 of the microscope.
Jpn. UM Appln. KOKAI Publication No. 48-7046 discloses a microscope comprising a revolver provided with a crown gear (a bevel gear) at a peripheral edge thereof and another gear held in engagement with the crown gear so that the revolver can be operated for rotary motion by manipulating a handle fitted to the gear. With a microscope having such an arrangement, however, the operator has to extend with an effort one of his or her arms upward to operate the revolver.
FIG. 15 schematically illustrates a known microscope having a configuration similar to the one shown in FIG. 14 but comprising an electric revolver assembly that allows an easy and efficient operation of the revolver. In FIGS. 14 and 15, the components that are similar to or the same as their counterparts are denoted by identical reference symbols.
The revolver 10 of the microscope is driven to rotate by a built-in electric motor. However, in order to drive the revolver 10 to rotate by means of an electric motor, the microscope is required to comprise additional components for driving the electric motor such as a power source unit 11 and a controller unit 12 provided with a control panel 12a. Because of these additional components, the electric revolver assembly of FIG. 15 is by far more costly than the one shown in FIG. 14.
Thus, a conventional manual-operation type revolver assembly of a microscope comprises a revolver located at an elevated position relative to the remaining components of the microscope to be operated for observing a specimen and, therefore, the operator is required to do a specific action of extending one of his or her arms simply to manipulate the revolver. Such a cumbersome action gives rise to a problem of causing considerable fatigue on the part of the operator if repeated for screening a large number of specimens and an additional problem of poor screening efficiency. A known electrically driven revolver assembly is, on the other hand, accompanied by the problem of higher cost due to additional components such as a power source unit and a controller unit.